exmh is available at http://beedub.com/exmh/.
Section MH explains how to get MH.
Tcl and Tk are available at http://www.tcl.tk/.
Expect is available from http://expect.nist.gov/.
You can get Metamail for MIME support; see the Section Metamail.
Faces are available from http://www.cs.indiana.edu/ftp/faces/. The individual databases are four compressed tar files:
facedir.tar.Z Accumulated personal faces
facesaver.tar.Z USENIX FaceSaver faces
logos.tar.Z Internet domain
logos
news.tar.Z Usenet news
hierarchy icons (not intended for email)
Get PGP at http://www.pgpi.org/.